The next stage of the battle over Central Maine Power’s planned transmission corridor will play out in the courts, after a state regulator suspended the project’s license Tuesday night. 

The decision from the Maine Department of Environmental Protection came within a day of a hearing on the ramifications of the referendum vote for a law seeking to block the power line. 

“In light of... the legal presumption of the validity of that law, along with the lack of readily identifiable, viable alternative transmission line routes around the Upper Kennebec Region, I find the approval of the Referendum ... requires suspension of the License,” DEP commissioner Melanie Loyzim wrote.

CMP’s parent company, Avangrid, has challenged the referendum as unconstitutional and is seeking a preliminary injunction against it in Superior Court. They had already paused construction on the power line while waiting for a ruling on that request, expected next month. 

Loyzim’s order requires CMP, within 30 days, to stabilize and secure its construction areas so that they don’t put public health or the environment at risk. Her order will also be in place until a ruling on the injunction request, or until the entire case is resolved if the request is denied. 

After that, she said she would separately take up the implications of an earlier stumbling block for the project — an August Superior Court decision overturning its one-mile public lands lease. That case is on appeal to the state Supreme Court. 

State officials hearing other appeals of the project said they would continue their work on a separate track, with hearings expected in early 2022. 

In a statement Wednesday, project CEO Thorn Dickinson expressed disappointment in the order, which he argued was unnecessary with construction already on hold. 

“Moreover, and perhaps most importantly, there has been no change in the real and serious need for this project to address climate change,” he said. “We remain committed to the construction of the corridor and the significant reduction of more than three million metric tons of carbon emissions it will bring to Maine and New England annually.” 

A group of Maine lawmakers wrote to Massachusetts Gov. Charlie Baker soon after the DEP order, asking him to pull his financial backing of the CMP corridor in light of the suspension. 

Craig Gilvarg, a spokesman for Baker’s energy agency, said in an email Wednesday morning that the administration is still reviewing the outcome of the referendum “and will be working with Avangrid and our regional partners on the path ahead to securing more affordable, renewable energy for Massachusetts.” 

In 2018, Massachusetts quickly turned to the CMP corridor after New Hampshire blocked the similar Northern Pass project, which was the Baker administration’s first choice to help meet his state’s climate goals by bringing Canadian hydropower onto the New England grid. 

Pete Didisheim is the advocacy director for a leading CMP corridor opponent, the Natural Resources Council of Maine, and said the choice of the Maine project was always a mistake. 

“It was a high-risk gambit by Massachusetts, and it’s not clear that they learned any lessons from the New Hampshire case,” he said in an interview Wednesday. “So Massachusetts is complicit in this debacle here. They underestimated the opposition that would emerge in the state of Maine… and they put their bet on a deeply distrusted company in CMP.” 

Tony Buxton, the general counsel to Maine’s Industrial Energy Consumer Group, a business collective that supports the corridor, said he thinks Massachusetts should and will stay the course with CMP in order to meet its climate goals. 

But he said the Maine DEP made a fair choice that showed “grace under pressure” to essentially put the corridor on ice while the referendum is clarified in court. 

“They’ve tried to place the questions in a place where there will be calm while the legal issues are resolved,” Buxton said in an interview Wednesday. “I can understand why state government needs to put this in a place where it is, at least temporarily, settled.” 

One issue that will likely need more of that clarification, whether in court or at the Maine Public Utilities Commission, is the legal definition of the “Upper Kennebec region,” where the CMP corridor and other lines like it are banned under the law enacted by the referendum. 

Attorneys sparred over the acreage and boundaries of that area during the state hearing earlier this week. It has major implications for if, where and how the corridor could be rerouted if the referendum stands. 

Loyzim’s order suggested that this was a major reason to suspend the project’s license: that more construction on a route that’s in doubt would be an unacceptable environmental impact. 

Hydro-Quebec spokeswoman Lynn St-Laurent said they respect the order but hope to see the referendum struck down in court as soon as next month, for the sake of the CMP corridor and the future of “strategic electricity transmission infrastructure” in New England.

Buxton also emphasized the vested interest of fossil fuel companies in seeing the corridor defeated. He said those energy competitors will continue to use this kind of playbook to fight renewable energy growth until states like Maine “confront that obstructionism and defeat it.”